;(function (doc, win) {

    var docEl = doc.documentElement,
        resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize';
        recalc = function () {

            var clientWidth = $(window).width();

            if (!clientWidth) return;

            docEl.style.fontSize = 100 * (clientWidth / 750) + 'px';
        };

    if (!doc.addEventListener) return;

    win.addEventListener(resizeEvt, recalc, false);

    recalc();

})(document, window);